topic GPIO status after power saving mode in Kinetis Microcontrollers

GPIO status after power saving mode

ethanchiu — Tue, 04 Sep 2018 10:12:24 GMT

Hi, i have confused for GPIO status out of control after wake up from power saving mode(LLS3).

i am coding on the MCU MKW31Z512 series.

before i go to the LLS3 mode, i have configured the GPIO to output push-pull.(ex. PTA19, PTB2...etc).

But the GPIO will out of control for can not set high or low level when i wake up from LLS3 mode by sleep timeout

I must configures the pin mux again to let GPIO back to normal.

Is something wrong with my setting?

Thank you!!

Re: GPIO status after power saving mode

jorge_a_vazquez — Wed, 05 Sep 2018 22:21:01 GMT

Are you using Connectivity software to get into LLS mode? I would like to recommend you to check the Application note:

http://cache.freescale.com/files/32bit/doc/app_note/AN4503.pdf

https://www.nxp.com/docs/en/application-note/AN5088.pdf

According to Reference Manual:

When in LLS mode, the I/O pins are held in their input or output state.
Upon wakeup, the PMC is re-enabled, goes through a power up sequence to full
regulation, and releases the logic from state retention mode. The I/O are released
immediately after a wake-up or reset event. In the case of LLS exit via a RESET pin, the
I/O default to their reset state.

Hope this could help you.

Best regards

Re: GPIO status after power saving mode

mjbcswitzerland — Wed, 05 Sep 2018 22:58:10 GMT

Hi Ethan

PMC_REGSC = PMC_REGSC_ACKISO; // acknowledge the isolation mode to set certain peripherals and I/O pads back to normal run state

Regards

Mark

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